The invention relates to a loudspeaker apparatus which comprises at least one sound generation means, a channel which conducts sound at least in part being arranged in one sound radiation direction of the sound generation means, which channel is suitable for directing sound emerging from the sound generation means along the course of the sound-conducting channel in such a way that the sound emerges from the loudspeaker apparatus at a second end—designed in the form of a sound outlet opening—of the sound-conducting channel at a radiation angle defined by the sound outlet opening.
Loudspeaker apparatus which radiate the generated sound omnidirectionally have long been prior art. In this case a mainly tapered sound-reflecting medium is positioned in front of the sound generation unit in such a way that the radiated sound is reflected by the walls of the taper and is radiated at a large angle radially around the axis, the axis of the taper. Technical use is made of this in sirens and alarm units for example.
Corresponding apparatus, however, are also advantageous for the transmission of language and music, for example in the broadcasting of sound to large spaces, halls, stadia, shopping centres and the like. Accordingly, for example, it is provided in the case of the subject matter of the publication DE 41 08 409 A1 that an amplification of the sound pressure is achieved at the same time with the omnidirectional radiation of the sound. Accordingly, the sound-conducting channels are enlarged in the manner of a horn. This apparatus is therefore also referred to as a ring horn.
In the same way, the aim of the publication DE 198 49 401 A1 is to improve the efficiency of omnidirectionally radiating loudspeaker apparatus in order to be able to supply large areas in an acoustic manner even with a low amplifier power. A sound channel widened in the manner of a horn is described in this publication as well.
Similar apparatus were already developed at the beginning of the 20th century. In this way, for example, an omnidirectionally radiating horn has likewise been disclosed in the publication U.S. Pat. No. 1,943,499. In this publication embodiments are additionally described in which one or more coils are incorporated in the sound-conducting channel in order to enlarge the volume of the horn and thus additionally to increase the sound pressure. The lengthening achieved in this way additionally increases the sound pressure. In addition, depending upon the design of the coils and the radii of curvature it is possible for a preferred sound radiation direction to be specified.
A further example of an omnidirectionally radiating loudspeaker is disclosed in GB 248 061. The subject matter of the apparatus disclosed in it is a loudspeaker, in which the sound radiated by the latter—after the sound pressure has been amplified by a horn—encounters a mushroom-like apparatus which deflects the sound omnidirectionally.
A similar principle is disclosed in DE 10 2007 019 450. The subject matter of this publication is an omnidirectionally radiating and receiving acoustic horn. In the case of this acoustic horn too, a horn-like funnel neck is provided, at the thinner end of which the microphone or the loudspeaker can be arranged. The further end of the funnel neck has attached to it a taper-like solid body which together with the lower solid body forms a sound channel through which the sound is transmitted in such a way that it can emerge radially out of the apparatus.
The low sound pressure produced by the sound radiation over virtually the entire periphery of the apparatus is encountered in a specified direction by these apparatus according to the prior art with horn-like designs of the sound-conducting channel. Although this has positive effects for example on the sound pressure and the efficiency, it gives rise to various drawbacks which preclude an application of loudspeaker systems of this type in the hi-fi sector. In this way, for example, the usually high direction factor of horn loudspeakers counteracts the intention of an omnidirectionally radiating loudspeaker with virtually equal tone quality and volume over the entire space. On account of reflection inside the horn, it is possible for distortions and phase cancellations to occur and for the signal run time to be prolonged. This reduced fidelity in reproduction is undesired in the hi-fi sector. In the same way, the narrow band width and, in particular, the excessively high lower cut-off frequency in the case of an acceptable structural size preclude use in the private sector.
Modern loudspeakers and amplifiers already have performance characteristics which do not rely upon the high degree of efficiency of horn loudspeakers in particular in the case of the broadcasting of sound to relatively small spaces. Tone production as faithful as possible to the original is in fact a key requirement.
The object of the present invention is thus to provide an omnidirectionally radiating loudspeaker apparatus which avoids the drawbacks of sound-conducting channels shaped in the manner of a horn and which thus generates an improved acoustic result.